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Subnanometer Vacancy Defects Introduced on Graphene by Oxygen Gas
Yamada, Yasuhiro,Murota, Kazumasa,Fujita, Ryo,Kim, Jungpil,Watanabe, Ayuko,Nakamura, Masashi,Sato, Satoshi,Hata, Kenji,Ercius, Peter,Ciston, Jim,Song, Cheng Yu,Kim, Kwanpyo,Regan, William,Gannett, Wil American Chemical Society 2014 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.136 No.6
<P>The basal plane of graphene has been known to be less reactive than the edges, but some studies observed vacancies in the basal plane after reaction with oxygen gas. Observation of these vacancies has typically been limited to nanometer-scale resolution using microscopic techniques. This work demonstrates the introduction and observation of subnanometer vacancies in the basal plane of graphene by heat treatment in a flow of oxygen gas at low temperature such as 533 K or lower. High-resolution transmission electron microscopy was used to directly observe vacancy structures, which were compared with image simulations. These proposed structures contain CO, pyran-like ether, and lactone-like groups.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jacsat/2014/jacsat.2014.136.issue-6/ja4117268/production/images/medium/ja-2013-117268_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ja4117268'>ACS Electronic Supporting Info</A></P>
Yasuhiro Kuraishi,Kazuo Hara,Shin Haba,Takamichi Kuwahara,Nozomi Okuno,Takafumi Yanaidani,Sho Ishikawa,Tsukasa Yasuda,Masanori Yamada,Nobumasa Mizuno 대한소화기내시경학회 2023 Clinical Endoscopy Vol.56 No.4
Background/Aims: Post-endoscopic retrograde cholangiopancreatography pancreatitis (PEP) is the most common and serious complication of endoscopic retrograde cholangiopancreatography. To prevent this event, a unique precutting method, termed opening window fistulotomy, was performed in patients with a large infundibulum as the primary procedure for biliary cannulation, whereby a suprapapillary laid-down H-shaped incision was made without touching the orifice. This study aimed to assess the safety and feasibility of this novel technique. Methods: One hundred and ten patients were prospectively enrolled in this study. Patients with a papillary roof size ≥10 mm underwent opening window fistulotomy for primary biliary access. In addition, the incidence of complications and success rate of biliary cannulation were evaluated. Results: The median size of the papillary roof was 6 mm (range, 3–20 mm). Opening window fistulotomy was performed in 30 patients (27.3%), none of whom displayed PEP. Duodenal perforation was recorded in one patient (3.3%), which was resolved by conservative treatment. The cannulation rate was high (96.7%, 29/30 patients). The median duration of biliary access was 8 minutes (range, 3–15 minutes). Conclusions: Opening window fistulotomy demonstrated its feasibility for primary biliary access by achieving great safety with no PEP complications and a high success rate for biliary cannulation.
Gohda Syun,Ono Hironobu,Yamada Yasuhiro 한국탄소학회 2023 Carbon Letters Vol.33 No.2
Carbon dots (CDs) were synthesized from phloroglucinol (PG) by simple heat treatment at 220–230 °C in the atmosphere without catalysts and solvents. PG-CDs heated at 220–230 °C could be completely dissolved in environmentally friendly water and exhibited a photoluminescence (PL) peak at 485 nm with 85 nm of the full width at half maximum (FWHM). The water-soluble polymer-dot-like PG-CDs were estimated to be 1.6–3.2 nm in size, and exhibited a wide range of PL wavelength at 370–630 nm. Since the PG-CDs are water-soluble materials, PG-CDs could be homogeneously mixed with a polymer such as polyvinylpyrrolidone (PVP) in water as a solvent, and PG-CDs/PVP films were prepared. The films exhibited PL characteristics that convert ultraviolet light at 350 nm to visible light above 400 nm. Thus, using PG as the raw material which has widely been produced industrially, the water-soluble fluorescent PG-CDs/PVP films could be prepared at a low cost by environmentally friendly methods.
Validation of trip-induction system on a treadmill by comparison with a walking lane
Hazuki Miyata,Akiyama Yasuhiro,Yoji Yamada,Shogo Okamoto 제어로봇시스템학회 2019 제어로봇시스템학회 국제학술대회 논문집 Vol.2019 No.10
Trip-related falls, which account for a significant portion of falls by the elderly, often result in serious injury. A method to evaluate fall risk accurately will be increasingly required in the aging society. For this purpose, it is necessary to analyze the natural reaction motion against tripping. We therefore developed a device and method to induce tripping at an arbitrary time during walking on a treadmill. To evaluate the validity of that method, another experiment that induced tripping on a walking lane was conducted. The reaction motions in the two environments were then compared. In this study, we focused on the difference in the preferred walking speed between the ground and the treadmill. The results suggest that the joint patterns during the reaction motion become similar when the subjective velocities, not the physical velocities, become the same for the subject, whereas physical parameters such as the trajectory of the center of mass become similar when the physical velocities match. These results help to understand the reaction motion against tripping and to reproduce the natural reaction motion on the treadmill.
Discrete element simulations of continental collision in Asia
Tanaka Atsushi,Sanada Yoshinori,Yamada Yasuhiro,Matsuoka Toshifumi,Ashida Yuzuru Korean Society of Earth and Exploration Geophysici 2005 지구물리와 물리탐사 Vol.8 No.1
조립질 물질을 이용한 축소모형실험(예를 들어 모래상자실험)을 다양한 크기의 많은 지질학적 문제에 성공적으로 적용되어왔다. 이러한 물리적 실험은 개별요소법(DEM)을 이용하여 수치적으로도 수행될수 있다. 이연구에서는 현재 지구상에서 가장 중요한 지구조적 과정 중의 하나인 인도판과 유라시아판의 충돌문제를 시뮬레이션하기 위해 개별요소법을 적용하였다. 개별요소 시뮬레이션은 구조지질학뿐만 아니라 토질역학, 암석역학 등의 다양한 동역학적 분야에 적용되어왔다. 조사대상이 많은 작은 입자들의 조합으로 가정되기 때문에 개별요소 시뮬레이션은 거대하고 불연속적인 변형이 일어나는 대상을 다룰 수 있다. 그러나 DEM 시뮬레이션에서는 개개 입자에 대한 입력변수들과 전체 물성의 관계에 대해 거의 알려져 있지 않기 때문에 입력 변수들의 타당성을 검증하기 어려운 경우가 자주 있다. 그러므로 이전의 연구들에서는 시행착오에 의해 입력변수를 조정하여만 하였다. 이러한 어려움을 극복하기 위하여, 이 연구에서는 개별요소 시뮬레이션에 수치적인 이축 시험을 도입하였으며, 이러한 수치 시험 결과를 이용하여 충돌 모델에 사용되는 입력변수의 타당성을 검토하였다. 결과적인 층돌 모델은 동 아시아에서 관측되는 실제 변형과 매우 비슷하며, GPS 자료 및 동 아시아의 원위치 응력자료와 잘 대비된다.
Role of interleukin-6 in orthodontically induced inflammatory root resorption in humans
Ryuichi Kunii,Masaru Yamaguchi,Yasuhiro Tanimoto,Masaki Asano,Kunihiko Yamada,Takemi Goseki,Kazutaka Kasai 대한치과교정학회 2013 대한치과교정학회지 Vol.43 No.6
Objective: To determine the interleukin (IL)-6 levels in gingival crevicular fluid (GCF) of patients with severe root resorption after orthodontic treatment and investigate the effects of different static compressive forces (CFs) on IL-6 production by human periodontal ligament (hPDL) cells and the influence of IL-6 on osteoclastic activation from human osteoclastic precursor (hOCP) cells in vitro. Methods: IL-6 levels in GCF samples collected from 20 patients (15 and 5 subjects without and with radiographic evidence of severe root resorption, respectively) who had undergone orthodontic treatment were measured by ELISA. The levels of IL-6 mRNA in hPDL cells and IL-6 protein in conditioned medium after the application of different uniform CFs (0, 1.0, 2.0, or 4.0 g/㎠ for up to 72 h) were measured by real-time PCR and ELISA, respectively. Finally, the influence of IL-6 on mature osteoclasts was investigated by using hOCP cells on dentin slices in a pit-formation assay. Results: Clinically, the IL-6 levels were significantly higher in the resorption group than in the control group. In vitro, IL-6 mRNA expression significantly increased with increasing CF. IL-6 protein secretion also increased in a time- and magnitude-dependent manner. Resorbed areas on dentin slices were significantly greater in the recombinant human IL-6-treated group and group cultured in hPDL cell-conditioned medium with CF application (4.0 g/㎠) than in the group cultured in hPDL cell-conditioned medium without CF application. Conclusions: IL-6 may play an important role in inducing or facilitating orthodontically induced inflammatory root resorption.